The present invention relates to a vehicle driving monitor. The apparatus of the present invention is designed to monitor the limits at which a vehicle has been driven over a given period of time. The present invention is particularly useful to monitor rental cars or a fleet of vehicles. The monitor of the present invention records excessive G-forces on a vehicle caused by overly-aggressive or reckless driving. Therefore, a particular vehicle or a particular driver can be monitored by the vehicle owner to determine whether the vehicle is being driven within preselected limits set by the owner, whether the vehicle is being abused, and whether the vehicle is being driven in a manner to promote better fuel economy.
The owner of the vehicle can set selected maximum G-force limits by programming the monitor. When installed in a vehicle, the driving monitor measures and records the highest G-force readings on the vehicle caused by cornering, acceleration, and braking. These recordings can only be cleared using a security code or password. In addition, if power is removed before the recorded values have been cleared by the owner, a clocking circuit records the power disconnect, and indicates that power has been disconnected on a display screen of the monitor. The clocking circuit also records the total time that power was disconnected from the monitor. Warning lights and a tone generator may be provided to provide an indication to the driver that the driver is approaching the selected maximum limits to permit the driver to slow down in order to avoid exceeding the G-force preset limits.
Therefore, the vehicle driving monitor of the present invention advantageously provides an apparatus which allows the owner of the vehicle to decide how the vehicle is to be driven. A visual display permits the driver to monitor performance. In a preferred embodiment of the present invention, the monitor records the highest five G-force readings which exceed the selected G-force limit in an internal memory for the owner's review until the owner clears the memory using the password. The monitor of the present invention permits the owner of the vehicle to promote safe driving habits, to promote fuel economy, to identify unsafe or over aggressive drivers, and to reduce the service and maintenance cost on the vehicles. Promoting safe driving of vehicle also improves the vehicle's resale value. In some instances, it may be possible to obtain reduced insurance rates by monitoring how vehicles are driven.
The vehicle driving monitor of the present invention is equipped with a tri-level password system designed to control access to user defined G-force limits, allowable driver options, and acceleration or G-force records. Each password may illustratively be up to 10 digits long. Throughout the specification and claims, the terms driver, user, distributor, and manufacturer will be used. The driver is the person or persons operating the monitored vehicle. The driver's options include only how data is displayed on a display screen of the monitor. The driver cannot alter the data recorded by the monitor. The options available to the driver can be limited by higher access personnel.
The user is the person or persons authorized to set the maximum G-force values and to review recorded acceleration data. For instance, the user may be the owner of the vehicle or fleet of vehicles being monitored. Therefore, the terms "user" and "owner" are used interchangeably throughout the specification. The user password allows access to all of the features of the vehicle driving monitor. The user password may be changed by the user, the distributor, or the manufacturer.
The distributor is the person or persons who hold a master password. Typically, this will be a local distributor or rental agency manager. The distributor password also allows access to all of the features of the vehicle driving monitor. A primary purpose of the distributor password is to provide a backup password in case the user password is forgotten. The distributor password permits the user password to be changed without shipping of the monitor back to the manufacturer. The distributor password can only be changed by the distributor and the manufacturer.
The manufacturer password allows access to all user and distributor options of the vehicle driving monitor. In addition, the manufacturer password provides access to test and calibration routines. The manufacturer password or serial number for the monitor can be changed only by the manufacturer.
The monitor of the present invention provides a real time G-force measuring and recording instrument for monitoring G-forces on the vehicle which influence vehicle wear.
The vehicle driving monitor of the present invention determines whether a power supply has been removed from the monitor. Removal of the power supply means that the vehicle may have been operated in violation of the selected G-force limits while the monitor was turned off. An internal real time clock allows the user to determine whether the power has been removed from the monitor. If power has been removed, the real time clock is used to record the total amount of time that power was removed.
The driving monitor of the present invention stores all the G-force data in a non-volatile memory upon detection that power has been removed. Therefore, the information stored by the monitor is not lost if power is disconnected from the monitor.
The vehicle driving monitor of the present invention advantageously provides four independent directional acceleration signals. Therefore, the user can monitor G-forces in a forward direction, a reverse direction, a right direction, and a left direction on the vehicle. Separate records are stored for each of the four directions and the user can select maximum G-force limits for each of the four directions. G-forces which exceed these selected limits cause a violation counter to be incremented. In addition, the five highest G-force measurements which exceed the preselected limit for each of the four directions will be recorded and sorted.
The user may allow a visual warning such as a direction indicating LED or an audible warning before the driver exceeds the selected G-force limits for a particular direction. Either the audible warning or the visual warning, or both, may be disabled by the user. Therefore, the driver will not be warned prior to exceeding a preset G-force limit.
The driver may select to display only one of the four directions on a display of the monitor. In addition, the driver can select to continuously display the two active directions automatically. In the unidirectional mode, the number of times the limit has been exceeded in the display direction will also be displayed. Any of these driver options may be disallowed by the user.
The vehicle driving monitor of the present invention may be connected to a computer terminal to permit the information recorded by the monitor to be loaded into the computer. This permits bulk storage and listings of all real-time accelerations and may be used to analyze and record the driving history of a particular vehicle or a particular driver.
According to one aspect of the present invention, an apparatus powered by a power supply is provided for monitoring operation of a vehicle. The apparatus includes means for sensing G-forces on the vehicle. The sensing means generates an output signal proportional to the G-forces on the vehicle. The apparatus also includes means for storing G-force output signals generated by the sensing means which are higher than a selected limit, and means for detecting that the power supply for powering the apparatus has been disconnected. The detecting means provides an indication that the vehicle may have been driven without the sensing means and storing means in operation.
In the illustrated embodiment, the detecting means includes a counter for indicating the number of times the apparatus has been disconnected from the power supply. The detecting means also includes a clock which is activated upon disconnection of the power supply from the apparatus, and means coupled to the clock for storing the total length of time that the apparatus is disconnected from the power supply. The storing stores a predetermined number of the highest G-force output signals from the sensing means in a non-volatile memory upon detection of disconnection of the power supply from the apparatus by the detecting means.
Also in the illustrated embodiment, the apparatus further includes means generating a warning signal when a G-force output signal from the sensing means exceeds said selected G-force limit. The warning signal may be generated when the G-force output signal from the sensing means exceeds a threshold level which is a predetermined amount less than the selected G-force limit to permit a driver to correct a driving condition before the selected G-force limit is exceeded.
According to another aspect of the invention, an apparatus is provided for monitoring operation a vehicle. The apparatus includes a sensor for detecting G-forces on the vehicle. The sensor generates an output signal proportional to the G-forces on the vehicle. The apparatus also includes means for monitoring the output signals from the sensor, and an oven surrounding the sensor for heating the sensor to a substantially constant predetermined temperature, thereby improving the accuracy of the output signal from the sensor upon fluctuation of an ambient temperature adjacent the apparatus.
According to yet another aspect of the present invention, an apparatus is provided for monitoring operation a vehicle. The apparatus includes means for sensing G-forces on the vehicle. The sensing means generates output signals proportional to a forward G-force, a reverse G-force, a left direction G-force, and a right direction G-force on the vehicle. The apparatus also includes means for permitting an authorized user to set a selected maximum G-force limit for the forward direction, the reverse direction, the left direction, and the right direction. The apparatus further includes means for storing G-force output signals generated by sensing means which are higher than the maximum selected limit for the forward direction, the reverse direction, the left direction, and the right direction.
In the illustrated embodiment, the means for permitting an authorized user to set selected a maximum G-force limits includes means for analyzing a password of the user to determine whether the user is authorized to set the maximum G-force limits. The apparatus also includes means for displaying selected G-force output signals stored by the storing means, and means for permitting an authorized user to disable the displaying means.
Also in the illustrated embodiment, the G-force sensing means includes first and second acceleration sensors. The first acceleration sensor generates an output signal indicating both forward direction and reverse direction G-forces on the vehicle. The second acceleration sensor generates an output signal indicating left direction and right direction G-forces on the vehicle.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.